Electric switch contact mounting



Sept. 22, 1942. M. G. DAHL 2,296,809

ELECTRIC SWITCH CONTACT MOUNTING Original Filed April 8, 1938 my 70 lmwm T 3'0 llllii'lllll k Jo gig l!!.\||lll\ MAGNUS c. DAHL w INVENTOR 8 62 6 if 4 ATTORNEY5' Patented Sept. 22, 1942 2,296,809 ELECTRIC swrrcn CONTACT MOUNTING Magnus G. Dahl,

West Hartford, to The Arrow-Hart & Hegeman Da y, Hartford, Coma,

necticut Original 1941, Serial No. 396,920

Claims. (01. 200-166) This invention relates to contact mountings of electric switches. More particularly the invention relates to contact mountings on bodies of molded or pressed insulating materials.

It is an object of this invention to provide improved means for mounting contacts in insulating blocks of electric switches, particularly in the movable insulation contact carrying blocks of electromagnetically operated electric switches.

Another object of the invention is to provide means to prevent loss or inadvertent displacement of the wax which is commonly placed in back of the movable contact mounting means, such removal or loss being likely to occur due to the jarring and vibration of the switch as it operates, unless some means is taken to ensure the retention of the wax in its proper position.

Other objects and advantages of my invention will become apparent as it is described in connection with the accompanying drawing.

This application is a division of my prior application Serial No. 200,997, filed April 8, 1938, Patent 2,283,795, May 19, 1942.

In the drawing- Fig. i is a side elevation view of an electric switch embodying the invention, with the block upon which the stationary contacts are mounted shown partly in section.

Fig. 2' is a vertical section view taken through a contact supporting block embodying the invention.

Figure 3 is a similar view of a portion of Fig. 2, but showing in addition the contact supporting bar in position therein.

Fig. 4 is an end view showing in detail the recess in the movable contact supporting block in which the contact supporting bar is to be mounted and into which the wax is to be poured.

Fig. 5 is a detailed section view taken along line 5-5 of Fig. 2.

Fig. 6 is a view similar to Fig. 5 but with the contact supporting bar removed.

Referrin to the drawing, Fig. 1 shows an electromagnetic switch device in which the invention is particularly useful.

A contact carrying block of insulating material 30 is mounted on a metallic frame-work fabricated from parallel sheet metal side bars 22 joined at one end by a transverse bar 32. The

frame may be reciprocated by an electro-magnet,

all as disclosed in my co-pending application Serial No. 200,997.

The bridging contact 50 is resiliently mounted for axial movement on a flat irregularly-shaped metal post 58 and pressed against the enlarged slipped over the head Conn, assignor Electric Coma corporation of Conapplication April 8, 1938, Serial No. now Patent No.

Divided and this 2,283,795, dated May 19, application June 6,

end 56 thereof by a compressed spring 5| coiled about the shank of the post and pressing at one end against the insulating block 30 and at the other end against the contact 30.

The form and construction of the supporting post may be noted best by reference to Figs. 3" and 5. The supporting post in addition to having the enlarged head 56 and reduced shank 58 has, at its inner end (see Fig. 5) an enlarged head 60. In order that this post may be mounted in the supporting block 30 a narrow slot 62 is provided for each set of contacts. This slot 62 passes entirely through the insulating block 30 and through circular bosses 30 which form part of each contact mounting, these bosses being formed as extensions upon the insulating block 30. The bosses 30 are cylindrically bored to form a seat for the compression spring 6|. The. slot 62 in passing through the insulating block 30 merges into the cylindrical bores 6d at one end and at the other end enlarges into recesses 66 of rectangular shape. Into the opposite side walls of the passage 62 are cut or molded passages 68 extending from the circular bore 64 less than the whole way through the block 30.

In assembling the contacts on the mountings 30 the head 56 of the supporting post is first slipped through the slot (i2 from the rear until the enlarged head 60 is seated in the enlarged passage 66. The length of this passage'66 and the size of the head 60, as well as the size of the slot 62, are proportioned and arranged so that the head 60 is entirely within the insulation block 30. When in this position, a washer 10 may be 56 of the supporting bar and into the bottom of the cylindrical bore BL Then the spring 6| may be seated upon this washer and the bridging contacts may be mount-l ed upon the supporting post, as described in my co-pending application Serial No. 200,997. Wax may then be poured into the enlarged slot 66 to cover up the head 60 of the contact supporting bar. The wax will flow into the inner end of the recesses 68 which communicate with the enlarged slot 66. It will be noted that the communication of the recesses 68 with the enlarged slot 66 is in the nature of an ofiset or undercut, so that when the wax hardens no amount of vibration will permit it to jar loose and fall out of the insulating block 30. This is a valuable feature of my invention. In switches of this type, considerable vibration occurs and wax that may be used to cover up current carrying parts may very easily become loosened and fall out of its recess unless my invention is employed.

Usually the body 30 will be made of molded insulating material. 'In forming the recesses and passages, plunger-s are employed in cooperation with the mold form. To create the passage 65, a plunger can come in from the right (Fig. 6). To create the bore 64, slot 62 and recesses 68, another plunger can come in from the left (Fig. 6) Thus, the creation of the oifset or under cut provided by the communication of recess 68 and slot 66 involves no insurmountable melding problem, but on the other hand the invention provides a commercially-practical molded structure.

When the switch is assembled, the movable bridging contact buttons 53 may engage'with stationary or fixed contacts 82 and 84 which may suitably be mounted upon an insulating block attached to the base of the switch.

1, roviding a, passageway for wax to flow and. pro-' From the foregoing, it will be observed .that I i have provided a novel and effective means for mounting a movable contact upon its insulating support in such manner as to prevent loss of wax insulation during vibration or switch in its normal operation.

Although the embodiment tromagnetically operated switch, the principles of the invention may be applied equally to other electric switches. I do not limit my invention to the specific embodiment shown.

I claim:

1. A support for an electric contact comprising an insulatin body having a passage through it, a contact structure carried by said body including a post in said passage, an enlarged head on said post for holding it in said passage, said passage having intersecting recesses offset into its side walls providing a passageway for wax to flow and providing a shoulder preventing the wax, when cool, from displacement on occurrence of jarring Or vibration during use, and a member at one end of said passage forming a seal to prevent outflow of wax through said end while the wax is in a molten state.

2. Supporting structure fOr an electric contact comprising an insulating body, a passageway through said body having the portion of the passageway at one end angularly oifset from the portion at the other end, said offset portions being co-extensive in the mid-portion of the passageway to provide a shoulder on a body of wax flowed into said passageway and to prevent withdrawal Of said wax body, when cool, from the jarring of the shown is an, elecsaid post extends forming a passageway,

eluding a post in said passage, an enlarged head on said post for holding it in said passage, said passage having recesses offset into its side walls viding a shoulder preventingthe wax, when cool, from displacement on occurrence of jarring or vibration during use, a member through which seal against passing of wax through one end of said passage, a contact on'said post, and spring means urging'said contact against an enld of said post. I

4-. Supporting structure for an electric contact comprising an' insulating body, a passageway through said body having the portion of the passageway at one end angularly offset from the portion at the other end, to provide a shoulder on a body of wax flowed into said passageway and to prevent withdrawal of said wax body, when cool, from said passageway, a post in said passageway and having an enlarged head to prevent the. post from being withdrawn through one end of the passage, a member through which said post extends forming a seal against passing of wax through one end of said passage, a contact on said post, and spring means urging said contact against an end of said post.

5. A support for an electric contact comprising an insulating body having a recess molded into one face and a counter recess molded into another face, said recesses intersecting to form a communicating aperture and a shoulder for each recess, a contact supporting post passing through said aperture and having an enlarged head received in said counter recess and engaging its shoulder, a washer passing over said post'and into the first recess and engaging its shoulder, and wax flowed into said counter recess over said enlarged head and around its shoulder and onto said washer.

MAGNUS G. DAHL. 

